Smartcards and other secure devices are routinely used to identify personnel or provide other security features. For example, smartcards are often used to identify particular computer users, where authorized users may use a computing device or access a computing system after identification. As another example, smartcards are often used in television distribution systems, such as in cable and satellite television receivers, to control which customers receive service.
Hackers and other people routinely attempt to illicitly access secure information stored on smartcards or other secure devices. Different techniques have been used to access information stored on the smartcards and other secure devices, such as current analysis and electromagnetism analysis. Conventional smartcards previously used “dummy cycles” in an attempt to defeat these techniques. Dummy cycles represent periods of time where the conventional smartcards attempt to mask their normal operations. In theory, by randomizing when dummy cycles are used, it is more difficult to identify how the conventional smartcards operate and to access the secure information. However, dummy cycles typically create a recognizable signature that can be detected with accurate current analysis or electromagnetism analysis, allowing the protection provided by the dummy cycles to be easily overcome.